How to disable fcurve sync?
There is a simple solution I use in 2.76b. Just use nodes for those materials, and animate values in the nodes. It will block each material instance. But if you animate the same options in the properties editor - it will animate them all. It's a bug.
Note: To see your keyframes on the timeline you have to select the node.
And yes, check beforehand, whether or not you use the different materials indeed. I mean, material can be linked to the objects, and to their respective object data as well. So, this check may show, if you have multiple objects, sharing the same object data, hence the materials.
I did reproduce that situation, and I think, I found a solution to avoid the channels to be linked but not copied on material duplicated.
So the solution is pretty simple - DO NOT PRESS PLUS BUTTON to copy the material, instead use the numbered button which shows the number of shares. This works for me in Blender v2.76b on Windows XP 32 bit.
See the explanations below.
The problem:

The solution:


And please, don't tell Captain Disillusion about those buttons! ;-)